Some of my experience:
You can adjust 4 different music types of gain under Fine tuning- Music program- Audibility fine tuning-Sound category-Sound type, this is easier to understand than directly adjusting the gain under Fine tuning-Music program-Gain&MPO.
If you using a compilot to streaming the music, you can changing the fine turing data of Bluetooth audio+mic program from Music.
When the compilot and PC are connected via the AUX cable, the sounds quality is better than connected by BT.
I found that the sounds quality of DSL v5a adult fitting formula was good, but changing fitting formulas would affect all programs.
If I changing the compression type under Global tuning to semi linear or linear, sound quality will improves, but changes can affect all programs.